The term "anchor bolt" as used herein is intended to mean a bolt which is used in fixing a machine or other structures to bases, such as a rock bed, concrete and masonry.
Heretofore, various methods have been known for fixing an anchor bolt to a base. For example, one of the known methods is as described below. A hole is drilled in a base and a capsule comprising a casing, a thermosetting resin contained therein, e.g., an unsaturated polyester resin, and a-curing agent for the thermosetting resin disposed in isolation from the thermosetting resin, is inserted into the hole. An anchor bolt is driven into the hole by means of a hammer drill which has been coupled to the rear end of the bolt. The capsule in the hole is broken by the rotary percussion of the anchor bolt during the driving thereof, allowing the thermosetting resin to be reacted with the curing agent, so that a cured resin is formed and the inserted anchor bolt is fixed to the base. (See Examined Japanese Patent Application Publication No. 38-12863.)
However, the above-mentioned method has drawbacks in that when an anchor bolt is fixed to a base located in sea water or water, or to a base located on a shore, a reactive monomer component, e.g., a styrene monomer component, of the curable resin composition escapes and floats to the surface of the sea, thereby polluting the sea. Further, there is also a problem in that the escape of the reactive monomer leaves a portion of the resin remaining intact and uncured. This uncured resin sinks to the bottom of the sea, thereby polluting the sea.
In order to avoid such a pollution of the sea, a capsule for fixing an anchor bolt, in which each of a curable resin and a reactive monomer has a specific gravity of at least 1.05, has been proposed (see Unexamined Japanese Patent Application Laid-Open Specification No. 4-27528).
Further, there has been proposed a cartridge for use in fixing an anchor element, employing a surfactant in order to prevent a separation between an inorganic cement and an organic resin (see Unexamined Japanese Patent Application Laid-Open Specification No. 55-161197).
When the above-mentioned capsule disclosed in Unexamined Japanese Patent Application Laid-Open Specification No. 4-27528 (which contains a curable resin and a reactive monomer, each having a specific gravity of at least 1.05) is used in fixing an anchor bolt to a base located in sea water or water, or to a base located on a shore, the amount of reactive monomer which escapes and floats on the surface of the sea is reduced to some extent in comparison to the use of a capsule containing a curable resin and a reactive monomer each having a specific gravity-of from 1.02 (which is equal to the specific gravity of sea water) to less than 1.05. However,.the capsule of the above Japanese patent document cannot completely prevent the escape and floating of a component of the curable resin, so that a danger of polluting the sea still remains.
It has been known that an epoxy acrylate resin can be advantageously used for fixing an anchor bolt. An epoxy acrylate resin is superior to an unsaturated polyester resin in properties, such as alkali resistance and fixing strength between an anchor bolt and a base. However, an epoxy acrylate resin has a high hydrophilicity and, therefore, when an epoxy acrylate resin is used in a capsule for use in fixing an anchor bolt, there are disadvantages in that the fixing strength is likely to be greatly lowered, and the amount of reactive monomer which escapes and floats on the surface of the sea is increased.
In these situations, the present inventors have made extensive and intensive studies with a view toward developing a new type of capsule for use in fixing an anchor bolt which is free from the above-mentioned problems accompanying the conventional capsules; even though an epoxy acrylate resin that is capable of achieving a high fixing strength is used. As a result, it has unexpectedly been found that by the use of a capsule for use in fixing an anchor bolt, which comprises (1) a casing having a sealed construction or a fluid-tight construction, (2) a curable resin composition, contained in the casing, comprising an epoxy acrylate resin composed mainly of an ester of an epoxy resin with (meth)acrylic acid, and a reactive monomer, wherein each of the epoxy acrylate resin and the reactive monomer has a specific gravity equal to or greater than the specific gravity of sea water, (3) a curing agent for the curable resin composition, disposed in association with the casing and in isolation from the curable resin composition, wherein the curing agent comprises an organic peroxide, and (4) a surfactant contained in at least one member selected from the group consisting of the curable resin composition and the curing agent, or disposed in association with the casing and separately from the curable resin composition and the curing agent, wherein the primary casing is breakable by the action of an anchor bolt when the anchor bolt is driven into the capsule, not only does it become possible to stably fix an anchor bolt to a base located in sea water or water, or to a base located on a shore, with high strength, but also it is unlikely that any portion of the curable resin composition will escape and float to the surface of the sea. Thus the present invention enables the anchor bolt-fixing work to be safely done without a danger of polluting the sea. Based on the above novel findings, the present invention has been completed.
Accordingly, it is an object of the present invention to provide a capsule for use in fixing an anchor bolt, by the use of which not only does it become possible to stably fix an anchor bolt to a base located in sea water or water, or to a base located on a shore, with high strength, but also it is unlikely that any portion of the curable resin composition will escape and float to the surface of the sea, thus enabling the anchor bolt-fixing work to be safely done without a danger of polluting the sea.
The foregoing and other objects, features and advantages of the present invention will be apparent from the following detailed description taken in connection with the accompanying drawings.